Coronary atherosclerosis is the major cause of death in women in the USA. Coronary artery bypass surgery decreases symptomatic and clinical evidence in cardiac ischemia but does not alter the underlying process. Patients may develop recurrent symptoms. Observational studies suggest that postmenopausal estrogen replacement therapy reduces cardiac morbidity by 50%. This study aims to establish the benefit of estrogen and progestin co- therapy in women with coronary disease.